Plastic resin products having a multicolored effect, such as stripes added or laminated to a resin material of a different color, are known. It is also known to produce solid colored resin material by adding colorant to a resin batch before mixing.
Japanese Patent No. 70-029,381 describes a foam polyolefin having a fine homogeneous closed-cell structure The foam is crosslinked, and is made by a batch process.